A group of drivers who have implantable cardioverter defibrillators are petitioning the Federal Motor Carrier Safety Administration for an exemption that would allow them to return to the road driving a truck.

On Tuesday, FMCSA will publish a notice on the Federal Register laying out the exemption requests from 15 individuals who have implantable cardioverter defibrillators.

An implantable cardioverter defibrillator, or ICD, is a device used for preventing sudden death in patients with known, sustained ventricular tachycardia or fibrillation. Tachycardia is a sustained heartbeat of 100 beats per minute or more and fibrillation is an irregular, rapid heartbeat.

According to the American Heart Association, the ICD is placed under the skin and keeps track of the heart rate. Thin wires connect the ICD to the heart. If an abnormal heart rhythm is detected the device will deliver an electric shock to restore normal heart beat.

The federal regulation 391.41(b)(4) states that a driver “has no current clinical diagnosis of myocardial infarction, angina pectoris, coronary insufficiency, thrombosis, or any other cardiovascular disease of a variety known to be accompanied by syncope, dyspnea, collapse, or congestive cardiac failure.” (Editor’s note: emphasis added for clarity in defining the terms)

FMCSA provides medical advisory criteria to medical examiners to follow when determining if a driver is medically certified to drive a truck.

According to the Federal Register notice, the advisory related to 391.41(b)(4) states that the phrase “has no current diagnosis of” means that the driver should not have “a clinical diagnosis of” a current cardiovascular condition or a cardiovascular condition which has not fully stabilized regardless of a time limit.

The advisory also states that the phrase “known to be accompanied by” is designed to include a clinical diagnosis of a cardiovascular disease which is accompanied by symptoms of syncope, dyspnea, collapse or congestive cardiac failure; and/or which is likely to cause syncope, dyspnea, collapse, or congestive cardiac failure, the Federal Register notice states.

In 2014 three individuals petitioned the agency for an exemption from the regulation that would allow them to drive in interstate commerce. The agency did not issue a final decision on those requests because, according to the Federal Register notice, the agency was in the process of gathering and analyzing additional data concerning ICD use and driving.

The agency is republishing the initial three requests for exemption, along with 12 more. The individuals have ICDs that were implanted anywhere from more than a decade ago to as recently as this past year. All of the individuals have letters from physicians essentially vouching that their ability to drive would not be adversely affected by the ICDs.

FMCSA will begin accepting comments on the exemption request on Tuesday, April 21.